1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly to a semiconductor device suitable for a liquid crystal panel with TFTs and a photoelectric conversion apparatus.
2. Related Background Art
The size of a TFT panel is rapidly becoming large nowadays, under the circumstances of developments of manufacture techniques for TFT liquid crystal panels and wide applications of area sensors with photoelectric conversion elements such as X-ray image-pickup apparatuses. Together with a trend of large size panels, a pattern pitch is also becoming fine and a panel manufacture yield is lowering. The reasons for this may be ascribed to the following.
(1) As the size of a panel becomes large, a wiring distance per panel elongates and a wiring disconnection probability rises.
(2) As the pattern pitch becomes fine, the number of TFTs per panel and the area of wiring cross points per panel increases and a short circuit probability rises.
(3) Occurrent of electrostatic defects (ESD). As the size of a panel becomes large, a contact area with the panel increases so that the amount of static electricity to be caused by friction or peel-off increases and quick and uniform discharge of electricity is becoming more difficult. As the pattern pitch becomes fine, the number of pattern cross points increases and the probability of defective panels to be caused by ESD rises.
Of these reasons, the reason (3) of ESD can be effectively alleviated by connecting the common electrode bias line and gate lines, or the common electrode bias line and gate and transfer lines, to a metal line to maintain these lines at the same potential. However, these connected lines are required to be separated at an intermediate process of manufacturing a semiconductor device with a TFT panel. For example, this separation can be performed by a panel slicing process which uses a blade made of diamond grains solidified with resin. Since the metal lines are cut, some reliability problem may occur such as abnormal wiring to be caused by metal particles or chips, short circuit of metal lines to be caused by metal expansion, metal fatigue and corrosion to be caused by water or heat during the slicing.